Described below are code sequences and radio stations, especially mobile stations or base stations, which are configured accordingly for the use of the code sequences.
The enormous speed at which technology is developing in the field of mobile radio communication systems has led in recent years to the development and standardization of what is referred to as the third generation of mobile radio systems, especially the UMTS (Universal Mobile Telecommunications System), among the aims of which is to make higher data rates available to the users of mobile stations, such as mobile telephone users for example.
Just in recent months a so-called enhanced up-link has been the focus of these development and standardization activities. This enhanced up-link is intended to provide increased data rates for the connection of a mobile station to a base station. To establish and maintain such an enhanced up-link the signaling channel E-HICH (Enhanced Up-Link Dedicated Channel Hybrid ARQ Indicator Channel) and E-RGCH (Enhanced Up-Link Dedicated Channel Relative Grant Channel) are provided in the direction from the base station to the mobile station.
With the E-HICH an “ACK: Acknowledge” or a “NACK: Not-Acknowledge” is signaled to the mobile station depending on whether a packet has been correctly received by the base station or not.
With the E-RGCH a signal is sent to the mobile station telling it whether it may transmit with the same, a higher or a lower data rate.
The data, especially data bits, which is sent over the signaling channels, especially over the same radio channel, to different mobile stations, is spread for subscriber separation with a code sequence, also called a signature sequence.
Since for example data will be sent to different mobile stations within the same radio channel, it is necessary to stamp onto the different data correspondingly different code sequences, to make it possible for the mobile stations sc to separate the data received via these radio channels and in a mobile station to only further process the data intended for this mobile station.
Whereas the enhanced up-link channel relates to a data transmission from the mobile station to the base station relates, the signaling channels, E-HICH and E-RGCH, describes the direction from the base station to different mobile stations.
For more details see:
    R1-041421 “E-HICH/E-RGCH Signature sequence”, Ericsson R1-041177, “Downlink Control Signal”, Ericsson all of 3GPP, 3rd Generation Partnership Program
The aim of further international development efforts is now to specify a set of code sequences or signature sequences which make possible an efficient implementation of these the signaling channels.